Skip to main content

Full text of "Laser Cutting"

See other formats

Lightbeams Structural Engineering System 

Makej Projects 

Lightbeams Structural 
Engineering System 

Written By: Kevin Gunn 


Laser cutter (1) Acrylic/plegixglass sheet (1) 


I wanted a way to build rigid, strong, high-precision objects that are much larger than I can 
cut in my personal laser cutter. In response, I designed Lightbeams -- which I'm now turning 
loose in the world. 

) Make Projects Page 1 of 8 

Lightbeams Structural Engineering System 

Step 1 — Lightbeams Structural Engineering System 

• I have small laser cutter (40W Full 
Spectrum Engineering Hobby 
Laser). I generally feed it wood or 
acrylic in 8"x12" chunks. However, 
I'd really like to make things that 
are much bigger than that -- like 
my next 3D printer. I want to 
design a printer that is bigger, more 
rigid and with tighter tolerances 
than my current Cupcake-derived 

• My solution was to design a rigid, 
extensible structural framework 
based on 0.22-inch acrylic. Since 
they're clear AND made on a laser, 
I call them "Lightbeams". 

) Make Projects 

Page 2 of 8 

Lightbeams Structural Engineering System 

Step 2 




li :! | : 

:^~ :: "UV 



: \As 


i • 

1 : 

1 ; 

• Each beam is formed from a basic 
repeating "1U Girder pattern". You 
can see it pictured here. 

• It's designed so that you get nice 
repetition of the mounting holes in 
all three dimensions. 

• I wanted to do this in metric (really 
America, get out of the Middle 
Ages!), but I live in the U.S. and 
have many fewer choices in 
materials (such as steel rods of a 
given length) if I use metric. 
Fortunately, this system is easy to 
use with metric bits as well. 

• Doesn't look like much as a single 
unit, but it took me nine iterations 
to get here! 

) Make Projects 

Page 3 of 8 

Lightbeams Structural Engineering System 

Step 3 

• By repeating the 1U basic form we 
can now make interesting 

• This one is a 4U Girder side. The 
small holes repeat every inch and 
can be used as mounting points for 
whatever you need to attach to the 
Lightbeam. The big holes allow you 
to route wiring or anything else 
through the interior of the structure. 

• The rectangular cutouts allow us to 
add "girder cores" to the system 
that keep it very rigid and square. 

) Make Projects 

Page 4 of 8 

Lightbeams Structural Engineering System 

Step 4 

• And here is just such a Girder Core! 

• The 4 little mounting holes allow you to mount electronics or other items INSIDE the beam 
if you so choose. 

• They also allow you to connect beams to one another at right angles as this core piece 
also forms the end cap on one end of the beam (I tried to reduce/reuse/recycle parts 
wherever possible to reduce the number of unique parts required to build things). 

• The big hole in the center allows wiring or other "stuff" to route through the center of the 

) Make Projects 

Page 5 of 8 

Lightbeams Structural Engineering System 

Step 5 

• Here's how a beam is built! Just 
glue the parts together with 
homemade acrylic cement. 

• Homemade acrylic cement? Oh... 
just dissolve all your waste acrylic 
bits in acetone to make a thick 
glue. Welds acrylic together and is 
virtually free! 

• By staggering 211 sides and 4U 
sides you get a very strong beam. 
The core pieces make this very 
square and very rigid. 

Step 6 

• The Cores are also the "male" end caps for a beam. One part, two functions. 

• This works really well because the screw holes and the main hole in the cores/ends match 
the spacing of those on the side of a girder. This means you can bolt an end cap onto the 
side of a girder to make a right angle between two beams. 

• The alignment of the big hole also means you can run wiring from one axis into another 
within the beam. 

• Note: the vertical beam pictured was a prototype that does not include all the routing holes. 

) Make Projects 

Page 6 of 8 

Lightbeams Structural Engineering System 

Step 7 

• From this basic system it is very 
easy to create any kind of mounts 
you might need for whatever you 
wish to build. 

• Pictured is a linear motion rod 
salvaged from an old printer. The 
rod is held tightly simply via a 
compression fit. 

• All you need to do is make sure 
your 1/8-inch diameter screw holes 
form a square one inch on each 

• If you build a structure for linear 
motion using Lightbeams, rods 
spanning your structure will be 
extremely parallel even over 
several feet of run. 

) Make Projects 

Page 7 of 8 

Lightbeams Structural Engineering System 

Step 8 

• So that's the basic overview. Use 
the system to make 3D printers, 
CNC frameworks, robotics or 
whatever else you might need! 

• It took quite a few prototypes to get 
this far (see the picture?), but we 
can go much, much farther! 

• Add to the system! Like everything 
here, the license on this is Creative 
Commons share-alike by 
attribution. Put simply, do whatever 
you want with it but (a) give credit 
where credit is due and (b) any 
modifications or additional modules 
you create for the framework you 
must share back in the same way. 
Basically: play nice! 

GET THE FILES???? Easy... get 
them here: 

How long your project takes and the materials required completely depends on what you plan to 
do with it! Big structures = lots of material! 

st generated on 2012-11-13 10:36:42 AM. 

) Make Projects 

Page 8 of 8